Ignition coil for battery-ignition apparatus



J. BOHLI March 24, 1931.

IGNITION COIL FOR BATTERY IGNITION APPARATUS Filed Jan. 10, 1929 Patented Mar. 24, 1931 UNITED STATES PATENT OFFICE JAKOB BOHLI, OF SOLOTHURN, SWITZERLAND, ASSIGNOR TO SGINTILLA A. G., OF SOLOTEURN, SWITZERLAND IGNITION COIL FOR- BATTERY-IGNITION APPARATUS Application filed January 10, 1929, Serial No. 331,671, and in Germany August 9, 1928.

In the usual ignition coils for battery ignition apparatus the sheet metal laminations forming the core are riveted together and the core is riveted or screwed to the coil casing which also consists of sheet metal. lVhere the cores are in two parts, these two parts are held together by clamps. By this arrangement eddy currents are formed in the joints, causing a magnetic field wiich has a damping effect on the magnetic flux in the iron core, so that the strength of the second ary spark is r duced.

According to the invention this disadvantage is overcome, by the laminations of the coil core being held together without a rivet or screw connection by the coil casing made of insulating material, so that there are no iron parts in such a position with respect to the coil core that a damping effect can be e):- erted on the magnetic flux.

In the accompanying drawing a constructional example of the invention is shown, Fig. 1 being a longitudinal section through an ignition coil having a core in two parts, Fig. 2 a View from below of the ignition coil and Fig. 3 a section through a primary terminal and the secondary terminal on line AB of Fig. 2, the coil being removed. G and H are the two halves of the iron core, which are E- shaped. On the middle limb of the core the coil F is mounted. The casing of insulating material also consists of two parts J and K and is preferably of round cross-section adapted to the shape of the coil with two diametrically opposed pockets which receive the lateral limbs of the core and press the loose laminations together. The core may be fixed in the pockets in the casing either by being clamped therein or by the insulating material being cast or pressed around the core. The two halves J, K of the casing are held together and to the base plate S by a screw bolt L which is preferably rectangular. M is the series resistance which is supported by an insulating body N and is covered by a protective cap 0. The protective cap and the supporting body for the resistance are also supported by the bolt L and thus fixed to the coil casing. The primary terminals Q are all housed in the upper part J of the casing, so that the line connections can be conveniently made. The high tension terminal R lies in the separating joint oi the easing in recesses provided in the two halves J, K of the casing and is held in position by the two halves being pressed together, which makes it very easy to mount. The cables 20, 22 lead in a known manner by way of a switch to the battery, the cable 21 leading to the primary current interrupter in the distributor and the terminal B being connected to the high tension distributor.

.Vhat I claim is:

1. An ignition coil comprising two laminated E-shaped core members enclosing a coil, a casing of insulating material divided into two half casings by a plane through the centre of the coil and at right angles to the plane of the laminations of the said core members, a base plate and a single central bolt clamping together the aforesaid parts into a single assembly.

2. An ignition coil as claimed in claim 1 wherein an insulating body and cap for a resistance are also clamped to the assembly by the said central bolt.

An ignition coil as claimed in claim 1 wherein an insulating body and cap for a resistance are also clamped to the assembly by the said central bolt and a high tension terminal of the said coil is clamped by the same bolt in a round aperture recessed equally in the two half casings.

In testimony whereof I have signed my name to this specification.

JAKOB BOHLI. 

